Cluttering (also called tachyphemia or tachyphrasia) is a speech and communication disorder characterized by a rapid rate making speech difficult to understand, erratic rhythm, poor syntax or grammar, and words or groups of words unrelated to the sentence.

"Cluttering is a fluency disorder characterized by a rate that is perceived to be abnormally rapid, irregular, or both for the speaker (although measured syllable rates may not exceed normal limits). These rate abnormalities further are manifest in one or more of the following symptoms: (a) an excessive number of disfluencies, the majority of which are not typical of people with stuttering; (b) the frequent placement of pauses and use of prosodic patterns that do not conform to syntactic and semantic constraints; and (c) inappropriate (usually excessive) degrees of coarticulation among sounds, especially in multisyllabic words".[2]

Spoonerisms, malapropisms, Colemanballs, and Freudian slips are examples of cluttering. Stuttering as a common term often refers to the speech disorder of cluttering, rather than to the speech disorder of stuttering. Cluttered speech is exhibited by normal speakers, and is often referred to as stuttering—this is especially true when the speaker is nervous, where nervous speech more closely resembles cluttering than stuttering.

Cluttering is sometimes confused with stuttering. Both communication disorders break the normal flow of speech. However, while stuttering is most often analyzed as a speech disorder, cluttering is a language disorder. In other words, a stutterer has a coherent pattern of thoughts, but can't express those thoughts; in contrast, a clutterer has no problem putting thoughts into words, but those thoughts become disorganized during speaking. Cluttering affects not only speech, but also thought patterns, writing, typing, and conversation.[3]

Stutterers are usually dysfluent on initial sounds, when beginning to speak, and become more fluent towards the ends of utterances. In contrast, clutterers are most clear at the start of utterances, but their speaking rate increases and intelligibility decreases towards the end of utterances.

Stuttering is characterized by struggle behavior, such as overtense speech production muscles. Cluttering, in contrast, is effortless. Cluttering is also characterized by slurred speech, especially dropped or distorted /r/ and /l/ sounds; and monotone speech that starts loud and trails off into a murmur.

A clutterer described the feeling associated with a clutter as:

“

It feels like 1) about twenty thoughts explode on my mind all at once, and I need to express them all, 2) that when I'm trying to make a point, that I just remembered something that I was supposed to say, so the person can understand, and I need to interrupt myself to say something that I should have said before, and 3) that I need to constantly revise the sentences that I'm working on, to get it out right.[4]

Because clutterers have poor awareness of their disorder, they may be indifferent or even hostile to speech-language pathologists. Delayed auditory feedback (DAF) is usually used to produce a more deliberate, exaggerated oral-motor response pattern. Other treatment components include improving narrative structure with story-tellingpicture books, turn-taking practice, pausing practice, and language therapy.

Battaros was a legendary Libyan king who spoke quickly and in a disorderly fashion. Others who spoke as he did were said to suffer from battarismus.[7] This is the earliest record of the speech disorder of cluttering.

In the 1960s, cluttering was called tachyphemia, a word derived from the Greek for "fast speech." This word is no longer used to describe cluttering because fast speech is not a required element of cluttering.

Deso Weiss described cluttering as the outward manifestation of a "central language imbalance."[8]

The First World Conference on Cluttering was held in May 2007 in Razlog, Bulgaria.[9] It had over 60 participants from North America, Europe, the Middle East and Asia.[10]